Okay, so after about an hour of searching through the web, I'm still having issues trying to create a local DB connection in ASP.net.
I need to create a connection to a local database file, and then simply loop through each record in a table. I'm not sure which file extension to use here (.aspx, .vbhtml, .cshtml?)
This is what I currently have from this W3school tutorial,
' Create local connection to DB file
#{
var db = Database.Open("Properties.mdf");
var query = db.Query("SELECT * FROM Properties");
}
<div id="pagewrap">
' Loop through records
#foreach(var row in query)
{
<p>#row.StreetAddress</p>
<p>#row.City</p>
<p>#row.State</p>
}
</div>
I'm currently getting a Connection string "Properties.mdf" was not found. error when running the above code. Any help is greatly appreciated.
That is because "Properties.mdf" is not a connection string. The mdf file cannot be opened just like this on its own - it needs a proper sql server database service. Exemplary connection string could look like this
var db = Database.Open("Server=.\SQLExpress;AttachDbFilename=Properties.mdf;Database=mydatabase;Trusted_Connection=Yes");
Although you need to have sql server installed (in this case your sql server instance would be called SQLExpress). and the connection string highly depends on what version of SQL Server you want to connect to.
Please refer to MSDN article.
Related
We store a template for building SQL Server CE connection strings in our web.config and use string.format to set the data source and temp path values.
In the web.config, the template for the DB connection string is:
"Data Source={0}; Temp Path={1}; Mode=Read Only"
In the web.release.config, we use to build deployment packages, the template for the DB connection string is:
Data Source={0}; Temp Path={1}
Now we only use the SQL Server CE database for read only operations. So, being a smartypants, I thought I would remove the connection string transform in the web.release.config and just always use the read only connection string from the web.config.
This worked fine for the database I was testing. But the same code running with a different SQL Server CE database fails with the following exception:
Exception 'System.Data.SqlServerCe.SqlCeException' with message 'The
database is opened with a read-only connection. Can't perform
post-initialization operations like re-building indexes and upgrading
public tracking. Please re-open with a read-write connection. [
Database name = D:\inetpub\wwwroot\MyApp\App_Data\Storage.sdf ]'
We are using the System.Data.SqlServerCe.4.0 provider
Why in my release build that is deployed to a server does read only access fail for some SQL Server CE databases but not others? It is the same code, just pointing at a different .SDF file. The .SDF files have the same schema, just different data.
Is the driver trying to rebuild indexes because the .SDF file is in some older format? Should we never use a readonly connection in production? Is that why the original code had the transform? why do they all work with a readonly connection on my Windows 7 workstation?
You should always specify a temp path, as moving databases between OS platforms/versions can require index rebuilds.
See my blog post post here: http://erikej.blogspot.dk/2009/08/running-sql-compact-from-cd-rom-read.html for more detailed info.
I am attempting to configure the connection string in web.confg for an ASP.NET app to connect to Azure DB. I am new to this but am familiar with sql configuration strings to SQL Server. How do I configure the login and data source in the connection string I am building. I haven't ever dealt with the cloud like this. If my db name is DB1 how do I set the Azure path for the data source portion of the connection string. NOTE: I know where to configure it in web.config and know to create a connection object.
Thanks.
In the Azure portal, you can navigate to your database's dashboard and click 'Show connection strings' on the right side. See the first screenshot on the below tutorial:
http://azure.microsoft.com/en-us/documentation/articles/sql-database-dotnet-how-to-use/
To answer your original question, "Data Source" means the same as "Server", it is just your server name, i.e. blah.database.windows.net. All of the connection string keywords (including their synonyms) are documented here: https://msdn.microsoft.com/en-us/library/system.data.sqlclient.sqlconnection.connectionstring%28v=vs.110%29.aspx
I have a website that uses asp.net 3.5 and Sql server 2008 as backend data store . now we want to add a new page to our website . but the data that we want to share in this page is already being created and saved by a FoxPro software in one of our local systems.
I've no experience in FoxPro . is there any way to use this data in our site ? specially without being have to create a new database in server and importing or writing all records all over again ? what is the best way in such a situation ?
by the way , is it possible to change the extension of a FoxPro database or not ? something like Database.customExt ?
You can connect to a FoxPro database using an OLEDB datasource in ADO.NET. It's up to you whether you feel the need to import the data into SQL Server or just access it directly in FoxPro. It would depend on whether you want to join the data with the SQL Server data in queries for one thing.
In addition to the answers that you already got. You might be interested in using LINQ to VFP or VFP Entity Framwork Provider to make the data access even easier by using LINQ.
You could create a linked server to this Foxpro Database.
Also, Foxpro tables can have any extension. However, you'll have to specify the extension when using the table or database. For Example:
OPEN DATABASE MyFoxProDatabase.customExt
USE mytable.custonExt
You have several options for structuring your data access to FoxPro. You can put the ADO.NET data access code in the codebehind, in it's own c# library or use the objectdatasource for 2 way binding.
private void LoadData(string parameter)
{
string sql = "SELECT a.myfield FROM mytable.customExt a WHERE a.whereField=?";
using(OleDbConnection conn = new OleDbConnection(myConnectionString))
{
using (OleDbCommand command = new OleDbCommand(sql, conn))
{
command.Parameters.AddWithValue("#Parameter", parameter);
try
{
conn.Open();
using(OleDbDataReader dr = command.ExecuteReader(CommandBehavior.CloseConnection))
{
myGridView.DataSource = dr;
myGridView.DataBind();
}
}
catch (Exception ex)
{
throw;
}
}
}
}
Here is a sample connection string to use in web.config:
<add name="myData" connectionString="Provider=VFPOLEDB.1;Data Source=C:\MyFiles\" providerName="System.Data.OleDb"/>
I belive ou can use a custom extension to your FoxPro tables and databases. All your SQL statements would then need to explicitly use that extension.
SELECT t.MyField FROM MyTable.customExt t
While you can change the extension for a Visual FoxPro table, that only affects the DBF file. If the table has any memo fields, there's an associated FPT file, for which you can't change the extension. Similarly, if the table has an associated index file, it must have a CDX extension.
So, if the reason you want to change the extension is to allow multiple tables with the same filestem, don't. It's a good way to really mess things up.
Can we close all known/unknown connections to database with the code?
I'm using Access database and my application gives the following error:
"Could not use ''; file already in use. "
I don't know which connection is opened and no closed, so is there a way to close all application's opened connections?
When working with disposable objects you should use using so they will get disposed, and in this case even closed, when leaving the using block. Your code should look something like:
using (var connection = new OleDbConnection(connectionString))
{
connection.Open();
// Do work here; connection closed on following line.
}
Read about OleDbConnection.
UPDATE: I missed that you were accessing an access database, so updated the code to use OleDbConnection instead.
In normal condition, I can add schemas in the dbml file to empty database with code below.
But now when I run this code, I take the error "Cannot drop database "test" because it is currently in use." How can I do it?
Dim db As New UI_Class.UIData
If db.DatabaseExists Then
db.DeleteDatabase()
End If
db.CreateDatabase()
It might happen as your SQL Server Management Studio (SSMS) must be holding it.
Most likely something is connected to the db.
Common causes are:
Some other tool connected
Trying to delete the database you connected to.
Another user connected to the db.